Paraguna is Venezuela's largest refinery and requires large amounts of natural gas for petroleum refining.

US counterweight

In a separate development, Uribe announced that Colombia would formally request to join a regional development bank backed by Chavez that is to launch next month in Caracas, Venezuela's capital.

Uribe, who is Washington's closest ally in the region, said: "Our entrance into the Bank of the South is not a rejection of the World Bank or the Inter-American bank but an expression of solidarity and loyalty with the South American brotherhood."

Chavez has pushed the bank as a counterweight to US influence, especially the US-dominated World Bank, and as a path to economic independence for the region.